CODEWITHSUNDEEP
javanetbeans
Sholyhit
Sholyhit

Reputation: 9

Java class testing issues

Hello I have a problem testing this, as I get an error that the testing is not right, can you guys explain why and what are the mistakes? 

public void addDays(int x) {
    int y = year;
    day = day + x;     
    if (day > 31) {     
      day = day - 31;   
      addMonths(1); 

    } else if (day >= 29 && month == 2 && (isLeapYear(y))) {
      day = day - 29;
      addMonths(1);
    } else if (day >= 28 && month == 2 && !(isLeapYear(y))) {
      {
        day = day - 28;
        addMonths(1);

      }
    }
  }

and this is my test for this method (Im using Netbeans).

     @Test
   public void testAddDays() {
    Date z = new Date(31,11,2013);
    z.addDays(3);
 assertEquals(3, z.getDay());

}  
           @Test
   public void testAddDays1() {
    Date z = new Date(28,2,2016);
    z.addDays(3);
 assertEquals(2, z.getDay());
}  
              @Test
   public void testAddDays2() {
    Date z = new Date(29,2,2014);
    z.addDays(2);
 assertEquals(3, z.getDay());
}

I would like to know where are my mistakes and how can I fix them

Upvotes: 0

Views: 80

Answers (1)

Steve
Steve

Reputation: 493

One solution would be to replace your custom-built date arithmetic with the java.util classes Date and Calendar, unless there's a reason not to use them (such as this being a date calculation exercise), since those utility classes are standard and well-tested.

For consistency with the Calendar class, I'd recommend a (year, month, date) format instead of your (date, month, year). That will make it more convenient to test your code against java.util results.

So, to look at your test cases, using your Date(date, month, year) format, on the assumption that you're not allowed to use java.util:

  • testAddDays: This adds three days to Date(31, 11, 2013). Since 2013-11-31 is not a well-formed date, the constructor should change it to 2013-12-01. Adding three days is 2013-12-04, so getDay() should return 4.
  • testAddDays1: This adds three days to Date(28, 2, 2016), a leap year. The next three days are 2016-02-29, 2016-03-01, and 2016-03-02, so getDay() should return 2.
  • testAddDays2: This adds two days to Date(29, 2, 2014), a common year. Since 2014-02-29 is not a well-formed date, the constructor should change it to 2014-03-01. Adding two days is 2014-03-03, so getDay() should return 3.

One obvious bug in your addDays(int x) method is that it doesn't test for x greater than one month. If you're not worried that the code will be slow for large x, you could iterate through all the months with something like this:

if (x < 0) {
  subtractDays(x);
  return;
}
day += x;
while (day > 0) {
  int daysThisMonth;
  switch (month) {
    case 2: daysThisMonth = isLeapYear() ? 29 : 28; break;
    case 4: case 6: case 9: case 11: daysThisMonth = 30; break;
    case 1: case 3: case 5: case 7: case 8: case 10: case 12: daysThisMonth = 31; break;
    default: // ERROR.
  }
  addMonths(1);
  day -= daysThisMonth;
}

Note that this code depends on addMonths() ignoring day, which is a code maintenance problem. I'm assuming there's also a subtractDays() method; if not, you'll need to revise your addDays() to allow for negative x.

There may also be problems in your constructor; it needs to test for handle dates that do not conform with calendar standards.

Upvotes: 1

Related Questions